On November 3 the Irish calendars commemorate Saint Muirdeabhair, whose memory still flourishes in County Limerick at the holy well associated with his name. A diocesan historian gives an account of what is known of the saint and his locality:
Disert Murdewar, now called Dysert, in the parish of Robertstown. Each part of this compound word is still preserved as if they had no relation to each other. The first part in the townland of Dysert, and the second in that of Morgans, the name of the adjoining parish which originally included Dysert, as the parish is called in old documents Dysert-merogan, Murirogan, and Morgans, as it is now called. It takes its name from St. Muirdebhair the wise, whose feast falls on the 3rd of November, according to the old calendars. The Felire of Aengus calls him a "synod's diadem." The Martyrology of Donegal at the same date has the following notice of him: "Muirdeabhair the wise of Disert Muirdebra in Ui Conaill Gabhra." O'Donovan thought this was the same as Dysert near Adare, but in this list of churches they are clearly distinguished. There is a famous holy well near the townland of Dysert at the head of a narrow creek that runs inland from the Shannon called Borrigone, which is much frequented by the people of the surrounding country. This is the holy well of the saint, but in course of time the "M " was changed into "B," which is of frequent occurrence in place names of this part of the country. There is no trace now of the old church, which must have been near the well.
Rev. John Begley, The Diocese of Limerick - Ancient and Medieval (Dublin, 1906), 110-111
Disert Murdewar, now called Dysert, in the parish of Robertstown. Each part of this compound word is still preserved as if they had no relation to each other. The first part in the townland of Dysert, and the second in that of Morgans, the name of the adjoining parish which originally included Dysert, as the parish is called in old documents Dysert-merogan, Murirogan, and Morgans, as it is now called. It takes its name from St. Muirdebhair the wise, whose feast falls on the 3rd of November, according to the old calendars. The Felire of Aengus calls him a "synod's diadem." The Martyrology of Donegal at the same date has the following notice of him: "Muirdeabhair the wise of Disert Muirdebra in Ui Conaill Gabhra." O'Donovan thought this was the same as Dysert near Adare, but in this list of churches they are clearly distinguished. There is a famous holy well near the townland of Dysert at the head of a narrow creek that runs inland from the Shannon called Borrigone, which is much frequented by the people of the surrounding country. This is the holy well of the saint, but in course of time the "M " was changed into "B," which is of frequent occurrence in place names of this part of the country. There is no trace now of the old church, which must have been near the well.
Rev. John Begley, The Diocese of Limerick - Ancient and Medieval (Dublin, 1906), 110-111